Trying to adapt Olaf's vif MTU patch for EL5.6's 2.6.18-238.9 kernel - patch in-line.

[Digimer <linux@alteeve.com>]

Hi all,

  As per the request on ##xen, I'm reposting this with patches and
diff's inline. Please ignore my earlier post.

  With a *lot* of help from Pasi yesterday, I was trying to get Olaf's
vif MTU patch
(http://lists.xensource.com/archives/html/xen-devel/2011-02/msg00352.html)
applied against the most recent EL5.6 (RHEL 5.6/CentOS 5.6) kernel
version 2.6.18-238.9.

  The patch as-is didn't apply cleanly, as there seemed to be a line
shift issue with common.h and xenbus.c. I manually added the lines and
created a new patch, but I screwed something up and it fails to compile.
I should note that I am /not/ a C programmer. :)

  Here is adapted patch:

====
--- linux-2.6.18.x86_64/drivers/xen/netback/common.h.orig	2011-04-15
17:46:12.730677042 -0400
+++ linux-2.6.18.x86_64/drivers/xen/netback/common.h	2011-04-15
17:57:57.490721792 -0400
@@ -76,8 +76,13 @@
 	struct vm_struct *tx_comms_area;
 	struct vm_struct *rx_comms_area;

-	/* Set of features that can be turned on in dev->features. */
-	int features;
+	/* Flags that must not be set in dev->features */
+	int features_disabled;
+
+	/* Frontend feature information. */
+	u8 can_sg:1;
+	u8 gso:1;
+	u8 csum:1;

 	/* Internal feature information. */
 	int can_queue:1;	/* can queue packets for receiver? */
@@ -110,6 +115,7 @@

 void netif_disconnect(netif_t *netif);

+void netif_set_features(netif_t *netif);
 netif_t *netif_alloc(domid_t domid, unsigned int handle);
 int netif_map(netif_t *netif, unsigned long tx_ring_ref,
 	      unsigned long rx_ring_ref, unsigned int evtchn);
@@ -142,7 +148,7 @@
 static inline int netbk_can_sg(struct net_device *dev)
 {
 	netif_t *netif = netdev_priv(dev);
-	return netif->features & NETIF_F_SG;
+	return netif->can_sg;
 }

 #endif /* __NETIF__BACKEND__COMMON_H__ */
--- linux-2.6.18.x86_64/drivers/xen/netback/interface.c.orig	2011-04-15
17:46:57.205456542 -0400
+++ linux-2.6.18.x86_64/drivers/xen/netback/interface.c	2011-04-15
17:50:46.027757042 -0400
@@ -90,34 +90,75 @@
 	return 0;
 }

-static int netbk_set_sg(struct net_device *dev, u32 data)
+void netif_set_features(netif_t *netif)
 {
+	struct net_device *dev = netif->dev;
+	int features = dev->features;
+
+	if (netif->can_sg)
+		features |= NETIF_F_SG;
+	if (netif->gso)
+		features |= NETIF_F_TSO;
+	if (netif->csum)
+		features |= NETIF_F_IP_CSUM;
+
+	features &= ~(netif->features_disabled);
+
+	if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN)
+		dev->mtu = ETH_DATA_LEN;
+
+	dev->features = features;
+}
+
+static int netbk_set_tx_csum(struct net_device *dev, u32 data)
+{
+	netif_t *netif = netdev_priv(dev);
 	if (data) {
-		netif_t *netif = netdev_priv(dev);
+		if (!netif->csum)
+			return -ENOSYS;
+		netif->features_disabled &= ~NETIF_F_IP_CSUM;
+	} else {
+		netif->features_disabled |= NETIF_F_IP_CSUM;
+	}

-		if (!(netif->features & NETIF_F_SG))
+	netif_set_features(netif);
+	return 0;
+}
+
+static int netbk_set_sg(struct net_device *dev, u32 data)
+{
+	netif_t *netif = netdev_priv(dev);
+	if (data) {
+		if (!netif->can_sg)
 			return -ENOSYS;
+		netif->features_disabled &= ~NETIF_F_SG;
+	} else {
+		netif->features_disabled |= NETIF_F_SG;
 	}

-	return ethtool_op_set_sg(dev, data);
+	netif_set_features(netif);
+	return 0;
 }

 static int netbk_set_tso(struct net_device *dev, u32 data)
 {
+	netif_t *netif = netdev_priv(dev);
 	if (data) {
-		netif_t *netif = netdev_priv(dev);
-
-		if (!(netif->features & NETIF_F_TSO))
+		if (!netif->gso)
 			return -ENOSYS;
+		netif->features_disabled &= ~NETIF_F_TSO;
+	} else {
+		netif->features_disabled |= NETIF_F_TSO;
 	}

-	return ethtool_op_set_tso(dev, data);
+	netif_set_features(netif);
+	return 0;
 }

 static struct ethtool_ops network_ethtool_ops =
 {
 	.get_tx_csum = ethtool_op_get_tx_csum,
-	.set_tx_csum = ethtool_op_set_tx_csum,
+	.set_tx_csum = netbk_set_tx_csum,
 	.get_sg = ethtool_op_get_sg,
 	.set_sg = netbk_set_sg,
 	.get_tso = ethtool_op_get_tso,
@@ -145,6 +186,8 @@
 	memset(netif, 0, sizeof(*netif));
 	netif->domid  = domid;
 	netif->handle = handle;
+	netif->can_sg = 1;
+	netif->csum = 1;
 	atomic_set(&netif->refcnt, 1);
 	init_waitqueue_head(&netif->waiting_to_free);
 	netif->dev = dev;
@@ -162,7 +205,8 @@
 	dev->open            = net_open;
 	dev->stop            = net_close;
 	dev->change_mtu	     = netbk_change_mtu;
-	dev->features        = NETIF_F_IP_CSUM;
+
+	netif_set_features(netif);

 	SET_ETHTOOL_OPS(dev, &network_ethtool_ops);

--- linux-2.6.18.x86_64/drivers/xen/netback/netback.c.orig	2011-04-15
17:46:58.141515042 -0400
+++ linux-2.6.18.x86_64/drivers/xen/netback/netback.c	2011-04-15
17:50:46.027757042 -0400
@@ -215,7 +215,7 @@

 static inline int netbk_max_required_rx_slots(netif_t *netif)
 {
-	if (netif->features & (NETIF_F_SG|NETIF_F_TSO))
+	if (netif->can_sg || netif->gso)
 		return MAX_SKB_FRAGS + 2; /* header + extra_info + frags */
 	return 1; /* all in one */
 }
--- linux-2.6.18.x86_64/drivers/xen/netback/xenbus.c.orig	2011-04-15
17:46:59.217582292 -0400
+++ linux-2.6.18.x86_64/drivers/xen/netback/xenbus.c	2011-04-15
18:13:20.700418792 -0400
@@ -345,6 +345,7 @@

 static int connect_rings(struct backend_info *be)
 {
+	netif_t *netif = be->netif;
 	struct xenbus_device *dev = be->dev;
 	unsigned long tx_ring_ref, rx_ring_ref;
 	unsigned int evtchn, rx_copy;
@@ -375,46 +376,40 @@
 				 dev->otherend);
 		return err;
 	}
-	be->netif->copying_receiver = !!rx_copy;
+	netif->copying_receiver = !!rx_copy;

-	if (be->netif->dev->tx_queue_len != 0) {
+	if (netif->dev->tx_queue_len != 0) {
 		if (xenbus_scanf(XBT_NIL, dev->otherend,
 				 "feature-rx-notify", "%d", &val) < 0)
 			val = 0;
 		if (val)
-			be->netif->can_queue = 1;
+			netif->can_queue = 1
 		else
 			/* Must be non-zero for pfifo_fast to work. */
-			be->netif->dev->tx_queue_len = 1;
+			netif->dev->tx_queue_len = 1;
 	}

 	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg", "%d", &val) < 0)
 		val = 0;
-	if (val) {
-		be->netif->features |= NETIF_F_SG;
-		be->netif->dev->features |= NETIF_F_SG;
-	}
+	netif->can_sg = !!val;

 	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4", "%d",
 			 &val) < 0)
 		val = 0;
-	if (val) {
-		be->netif->features |= NETIF_F_TSO;
-		be->netif->dev->features |= NETIF_F_TSO;
-	}
+	netif->gso = !!val;

 	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
 			 "%d", &val) < 0)
 		val = 0;
-	if (val) {
-		be->netif->features &= ~NETIF_F_IP_CSUM;
-		be->netif->dev->features &= ~NETIF_F_IP_CSUM;
-	}
+	netif->csum = !val;
+
+	/* Set dev->features */
+	netif_set_features(netif);

 	netdev_features_change(be->netif->dev);

 	/* Map the shared frame, irq etc. */
-	err = netif_map(be->netif, tx_ring_ref, rx_ring_ref, evtchn);
+	err = netif_map(netif, tx_ring_ref, rx_ring_ref, evtchn);
 	if (err) {
 		xenbus_dev_fatal(dev, err,
 				 "mapping shared-frames %lu/%lu port %u",
====

  And here is the compile output with errors:

====
drivers/xen/blkfront/blkfront.c: In function 'do_blkif_request':
drivers/xen/blkfront/blkfront.c:629: warning: format '%lx' expects type
'long unsigned int', but argument 4 has type 'sector_t'
drivers/xen/blktap/blktapmain.c:145: warning: 'set_blkif_reqs' defined
but not used
drivers/xen/netback/xenbus.c: In function 'connect_rings':
drivers/xen/netback/xenbus.c:387: error: expected ';' before 'else'
make[3]: *** [drivers/xen/netback/xenbus.o] Error 1
make[2]: *** [drivers/xen/netback] Error 2
make[1]: *** [drivers/xen] Error 2
make[1]: *** Waiting for unfinished jobs....
drivers/scsi/fcoe/fcoe.c: In function 'fcoe_interface_setup':
drivers/scsi/fcoe/fcoe.c:259: warning: unused variable 'ops'
drivers/scsi/fcoe/fcoe.c:256: warning: unused variable 'ha'
drivers/scsi/fcoe/fcoe.c: In function 'fcoe_interface_cleanup':
drivers/scsi/fcoe/fcoe.c:379: warning: unused variable 'ops'
drivers/net/phy/fixed.c: In function 'fixed_init':
drivers/net/phy/fixed.c:316: warning: unused variable 'duplex'
drivers/net/phy/fixed.c:315: warning: unused variable 'ret'
drivers/net/sfc/mtd.c:25:1: warning: "pr_fmt" redefined
In file included from include/asm/mach-xen/asm/page.h:8,
                 from include/asm/thread_info.h:12,
                 from include/linux/thread_info.h:21,
                 from include/linux/preempt.h:9,
                 from include/linux/spinlock.h:49,
                 from include/linux/capability.h:45,
                 from include/linux/sched.h:44,
                 from include/linux/module.h:9,
                 from drivers/net/sfc/mtd.c:12:
include/linux/kernel.h:261:1: warning: this is the location of the
previous definition
drivers/net/wireless/iwlwifi/iwl3945-base.c: In function 'store_antenna':
drivers/net/wireless/iwlwifi/iwl3945-base.c:3656: warning: unused
variable 'priv'
drivers/net/wireless/iwlwifi/iwl3945-base.c: In function
'iwl3945_cancel_deferred_work':
drivers/net/wireless/iwlwifi/iwl3945-base.c:3739: warning: passing
argument 1 of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/iwlwifi/iwl3945-base.c: In function
'iwl3945_pci_remove':
drivers/net/wireless/iwlwifi/iwl3945-base.c:4147: warning: passing
argument 1 of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/iwlwifi/iwl-3945-rs.c: In function
'iwl3945_rate_scale_flush_windows':
drivers/net/wireless/iwlwifi/iwl-3945-rs.c:190: warning: unused variable
'priv'
drivers/net/wireless/iwlwifi/iwl-3945-rs.c: In function
'iwl3945_bg_rate_scale_flush':
drivers/net/wireless/iwlwifi/iwl-3945-rs.c:223: warning: unused variable
'priv'
drivers/net/wireless/iwlwifi/iwl-3945-rs.c: In function
'iwl3945_collect_tx_data':
drivers/net/wireless/iwlwifi/iwl-3945-rs.c:297: warning: unused variable
'priv'
drivers/net/wireless/iwlwifi/iwl-3945-rs.c: In function 'rs_free_sta':
drivers/net/wireless/iwlwifi/iwl-3945-rs.c:464: warning: unused variable
'priv'
drivers/net/wireless/iwlwifi/iwl-3945-rs.c: In function
'iwl3945_get_adjacent_rate':
drivers/net/wireless/iwlwifi/iwl-3945-rs.c:585: warning: unused variable
'priv'
drivers/net/wireless/iwlwifi/iwl-agn.c: In function
'iwl_cancel_deferred_work':
drivers/net/wireless/iwlwifi/iwl-agn.c:2850: warning: passing argument 1
of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/ath/ath9k/main.c: In function 'ath_init_leds':
drivers/net/wireless/ath/ath9k/main.c:1122: warning: passing argument 1
of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/ath/ath9k/main.c: In function 'ath9k_stop':
drivers/net/wireless/ath/ath9k/main.c:2138: warning: passing argument 1
of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/ath/ath9k/main.c:2139: warning: passing argument 1
of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/ath/ath9k/main.c:2142: warning: passing argument 1
of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/iwlwifi/iwl-agn-rs.c: In function 'rs_free_sta':
drivers/net/wireless/iwlwifi/iwl-agn-rs.c:2849: warning: unused variable
'priv'
drivers/net/wireless/ath/ath9k/virtual.c: In function
'ath9k_wiphy_set_scheduler':
drivers/net/wireless/ath/ath9k/virtual.c:657: warning: passing argument
1 of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/rt2x00/rt2x00link.c: In function
'rt2x00link_stop_tuner':
drivers/net/wireless/rt2x00/rt2x00link.c:372: warning: passing argument
1 of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/rtl818x/rtl8187_dev.c: In function 'rtl8187_stop':
drivers/net/wireless/rtl818x/rtl8187_dev.c:1063: warning: passing
argument 1 of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/rtl818x/rtl8187_leds.c: In function
'rtl8187_leds_init':
drivers/net/wireless/rtl818x/rtl8187_leds.c:201: warning: passing
argument 1 of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/rtl818x/rtl8187_leds.c:202: warning: passing
argument 1 of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/rtl818x/rtl8187_leds.c: In function
'rtl8187_leds_exit':
drivers/net/wireless/rtl818x/rtl8187_leds.c:213: warning: passing
argument 1 of 'cancel_delayed_work_sync' from incompatible pointer type
drivers/net/wireless/rtl818x/rtl8187_leds.c:214: warning: passing
argument 1 of 'cancel_delayed_work_sync' from incompatible pointer type
make: *** [drivers] Error 2
+ exit 1
error: Bad exit status from /var/tmp/rpm-tmp.88561 (%build)


RPM build errors:
    Bad exit status from /var/tmp/rpm-tmp.88561 (%build)
====

  I applied it as Patch 28000. Here is the diff on the kernel-2.6.spec
(http://centos.alteeve.com/5.6/updates/SRPMS/kernel-2.6.18-238.9.1.el5.src.rpm).

====
--- kernel-2.6.spec.orig	2011-04-16 12:39:33.000000000 -0400
+++ kernel-2.6.spec	2011-04-16 13:55:15.000000000 -0400
@@ -75,7 +75,7 @@
 %define sublevel 18
 %define kversion 2.6.%{sublevel}
 %define rpmversion 2.6.%{sublevel}
-%define release 238.9.2%{?dist}%{?buildid}
+%define release 238.9.3%{?dist}%{?buildid}
 %define signmodules 0
 %define xen_hv_cset 15502
 %define xen_abi_ver 3.1
@@ -6318,6 +6318,7 @@
 Patch26314:
linux-2.6-md-dm-mpath-hold-io-until-all-pg_inits-completed.patch
 Patch26315:
linux-2.6-md-dm-mpath-wait-for-pg_init-completion-on-suspend.patch
 Patch26316:
linux-2.6-md-dm-mpath-fix-null-deref-when-path-parameter-missing.patch
+Patch28000:
linux-2.6-xen-netback-allow-large-mtu-until-frontend-connects.patch
 # adds rhel version info to version.h
 Patch99990: linux-2.6-rhel-version-h.patch
 # empty final patch file to facilitate testing of kernel patches
@@ -12392,6 +12393,7 @@
 %patch26314 -p1
 %patch26315 -p1
 %patch26316 -p1
+%patch28000 -p1
 # correction of SUBLEVEL/EXTRAVERSION in top-level source tree Makefile
 # patch the Makefile to include rhel version info
 %patch99990 -p1
====

  Any advice/help/clue-stick whacking would be much appreciated!

-- 
Digimer
E-Mail: digimer@alteeve.com
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